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Proceedings Paper

Experimental results of gain fluctuations and noise in microwave low-noise cryogenic amplifiers
Author(s): Juan D Gallego; Isaac López-Fernández; Carmen Diez; Alberto Barcia
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Paper Abstract

Applications like radio astronomy and space communications require ultimate sensitivity and make use of very particular receivers with state-of-the-art devices. Usually the receivers are cooled at cryogenic temperatures to reduce the noise even further. Noise temperatures of only a few times the quantum limit can be obtained in these conditions. During the past decade, Indium Phosphide HEMTs have demonstrated the best noise performance at cryogenic temperatures in the microwave frequency range of all active semiconductor devices, together with extremely low power consumption. For certain applications noise is not the only factor affecting the sensitivity. For example, gain fluctuations may play a dominant role in wide band radiometers. Unfortunately some of the factors that have contributed to improve the noise temperature have degraded the gain fluctuations. The operation at cryogenic temperatures also increases the fluctuations. This paper describes the experimental results obtained at the Centro Astronomico de Yebes (CAY) in the development of wide band cryogenic amplifiers. Special attention is paid to the influence of the bias point in noise and gain fluctuations. InP HEMTs from different foundries were tested. The amplifiers developed will be used in the Herschel ESA mission radiometers and the Atacama Large Millimeter Array (ALMA) receivers.

Paper Details

Date Published: 25 May 2004
PDF: 12 pages
Proc. SPIE 5470, Noise in Devices and Circuits II, (25 May 2004); doi: 10.1117/12.547097
Show Author Affiliations
Juan D Gallego, Observatorio Astronomico Nacional (Spain)
Isaac López-Fernández, Observatorio Astronomico Nacional (Spain)
Carmen Diez, Observatorio Astronomico Nacional (Spain)
Alberto Barcia, Observatorio Astronomico Nacional (Spain)


Published in SPIE Proceedings Vol. 5470:
Noise in Devices and Circuits II
Francois Danneville; Fabrizio Bonani; M. Jamal Deen; Michael E. Levinshtein, Editor(s)

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